The present invention relates to a process and apparatus for use in musical instruments. In particular, the invention identifies a chord played on a keyboard of a musical instrument, such as the accompaniment manual of an electronic organ, and identifies the root of the chord and the type of chord being played. The pedal circuitry (which may be responsive to either the pedal keys or manual stops controlling pedal tone sequences) of the musical instrument is then caused to play automatically either this root or a sequence of notes which is compatible with the identified root without actual playing of the pedals. The sequence can alternatively be produced automatically in the circuitry of the accompaniment division, if desired. In addition, an override feature is provided which overrides the chord identification feature when one or more pedal notes are played by the musician.
In an eletronic musical instrument with a pedal keyboard, it is desirable to have automatic pedal features. In previous instruments, systems have been developed which respond to playing with only one finger on the accompaniment manual. From this single note a complete accompaniment chord is constructed and the selected note or an octavely lower note is also used as the pedal note. A minor touch bar may also be provided to change from a major to a minor chord. In such systems, it is common for the pedal sequences to include the minor third when called for by the minor touch bar. In this way the pedal pattern is always musically correct and compatible with the accompaniment chord. These systems allow the beginning musician to obtain complete accompaniment chords and an automatic pedal sequence by playing only one finger on the accompaniment keyboard. However, if the musician wants to advance beyond one finger playing he is immediately faced with playing his own pedal and constructing his own chord.
Certain attempts have been made to overcome the foregoing limitations found in available musical instruments. For example, U.S. Pat. No. 4,248,118 discloses an apparatus for deriving the chord type and root of a chord being played. That system, however, operates on the principle of storing in digital memory the key patterns identifying all possible chords and chord combinations for comparison to the chord being played, or a rotated version of the same. When a match is found, the address of the matching stored pattern indicates the chord type. The chord being played is also rotated before the matching process commences in order to standardize the transposition. The number of rotations needed before a match occurs identifies the root of the chord. As one skilled in the art will appreciate, the number of key patterns identifying all possible chords and chord combinations is large. Because this system stores such patterns in digital memory, the chord identification function would appear to require a significantly large memory capability.
Unlike U.S. Pat. No. 4,248,118, the present invention performs the chord identification function through a logical sequence of tests which determine the existence of root intervals, the number of notes and the nature of the chord (e.g., whether the chord is a major or minor chord). The simplicity of the present invention allows chord identification of musically preferred chords based on the lowest note played without dedicating substantial memory space to that function.
Accordingly, it is a principal object of the present invention to provide a process which identifies the root and the type of a chord being played by the musician.
It is another object to provide a process adapted to cause the pedal or accompaniment circuitry of the musical instrument to play automatically the identified root or a sequence of notes which is compatible with the identified root.
It is yet another object to provide an override function whereby the musician may play the pedal keyboard thereby overriding the automatic chord identification system.
Yet another object is to provide a microprocessor adapted to implement the process of the present invention.